Method of manufacturing combustible gas



Sept. 15, 1936. H. J. CARSON METHOD OF MANUFACTURING COMBUSTIBLE GASFiled July 15, 1929 07% kotuwmv Patented Sept. 15, 1936 UNITED STATESMETHOD OF MANUFACTURING COMBUSTIBLE GAS Hiram J. Carson,

Cedar Rapids, Iowa.

Application July 15, 1929, Serial No. 378,256

4 Claims.

This invention relates to the production of combustible gas andby-products such as oils, tar, and ammonia from bituminous fuel ingasproducers and the utilization of part or all of the gases so producedin boilers and furnaces and the recovery of any remaining gases forother uses.

The principal objects of the invention are to effect economies in suchproduction and utilization by certain improvements in the methodsemployed.

The invention comprehends improved methods for: the production andrecovery of rich distillation gas and blue water gas, and alsooils,'tar, and ammonia from bituminous fuel in conjunction with theproduction of producer gas from the carbonized residue with thedistillation gases and products drawn off with a controllable amount ofor no admixture therewith of the producer gas; the utilization of partof the producer gas by combustion in regenerators for highlysuperheating steam for theformation of water gas, carbonizing the fueland/or the production of ammonia; the use of air and/or oxygen in thecarbonizing chamber for supplying a 25 part of the heat. required forcarbonization and/or for the water gas reaction; the immediateutilization of part or all of the producer gas so formed by combustionin a boiler or furnace with the combustion products therefrom used forpre- 30 heating the air for such combustion and/or the air for theproducer; the use of combustion products from the boiler or furnaceand/or steam as an endothermal agent for controlling the fuel bedtemperatures in the producer and the forma- 35 tion of combustible gas;an improved heat cycle in producers and boilers in combination whereby,the gasification and utilization of the heat of combustion of thefuel-are carried on in a highly efficient manner.

Zlhe invention also contemplates the removal of ash from the producer inliquid form to thereby eliminate the usual temperature limitationsbecause of the fusing temperature of the ash, and permit operation atrelatively high fuel bed tem- 45 peratures and capacities and the use ofcheap fuels with an avoidance of ash deposits in the boiler or furnaceand the usual operating difficulties and expense in connectiontherewith.

To insure theeasy liquefying of the ash the 50 invention contemplatesthe use of preheated air in the lower zone of the fuel column.

The invention contemplates the use of a fluxing material which may becharged with the fuel or introduced in the bottom zone of the fuelcolumn in any suitable manner such as blown in admixed with the blastingair as needed and desired. In the latter case the time interval requiredfor fiuxing material charged with the fuel to work down to the slagginglevel is avoided.

The invention further contemplates the introduction of combustible gaswith the blasting air in the bottom zone in case' of difliculty inslagging, which may for example be occasioned by a deficiency of.combustible in the fuel at the slagging level.

The blasting air may also be enriched with oxygen for further hasteningcombustion and liquefying the slag when desired.

'I'he invention also contemplates the use of part of the producer gasfor the alternate heating of two regenerative chambers and the heatstored therein in turn employed for highly superheating steam to bedelivered to and utilized in the carbonizing chamber or zone of theproducer.

Other objects of the invention will more clearly appear from thedescription and claims hereinafter following.

In the drawing forming a part of theapplication, a suitable apparatushas been disclosed for the effective carrying out of the improved methodor process. In said drawing, Figure 1 is a part vertical sectional view,part elevational view of a gas producer plant and associated steamgenerating boiler for effecting the complete cycle of steps of theimproved process. Figure 2 is a part top plan view and part horizontalsectional view of the regenerators and generator shown in Figure 1, thesectional view of the generator corresponding approximately to the lineA-A of Figure 1. Figure 3 is an enlarged vertical sectional view of thecarbonizing chamber used in the gas producer and shown in Figure 1. AndFigure 4 is an enlarged vertical sectional view, illustrating moreparticularly the details of construction of one of the air tuyeres,tuyere header and supplementary inlet valve associated therewith, shownis Figure 1.

The apparatus may now be described in detail.

In Figure 1, the gas producer I 2 is shown in section having mainly twozones. The lower zone I3 is the producer gas generating zone andcontains mainly incandescent fuel. The upper zone contains a carbonizingchamber I4 which is charged with fuel and ash fluxing material, aslimestone, when desired, through any suitable charging device as I5.

Air blast inlet means are shown at level I6 through valved inlets I611.and Ilia and also at level I! through valved inlets Ho. and Na.

Means for admitting steam at level I! when desired for use incontrolling fuel bed temperatures is indicated at l8. Air suppliedthrough l'la' may be mixed with the steam and admitted to the fuel atlevel I! as shown. Stack gas is preferably used as an endothermal agentfor controlling fuel bedtemperatures. This may be injected underpressure at level I'I as through supply pipes 53 or inspirated by andmixed with air as indicated at inspirator l8.

In heating operations with the gas containing I a relatively highpercentage of hydrogen a substantial portion of the total heat ofcombustion is lost in the latent heat of the water vapor in theresulting stack gases. The hydrogen content of the producer gas and thestack of water vapor loss are substantially reduced if. an endothermalagent such as stack gas containing little or no hydrogen is used.

The carbonizing chamber has an annular passage around it of a relativelylarge area, at 20 to lower the velocity of the gases leaving theincandescent fuel and reduce or avoid the carrying along of fine fuelparticles in the gases. The annular passage is preferably narrowed at 2|to increase the velocity of the gases and heat transfer to thecarbonizing chamber. The annular passageway 21! and 2! is preferablyenlarged at 22 tate the downward passage of the fuel and avoid stickingor hanging. The carbonizing chamber preferably contains an assembly'26in the center thereof. This assembly is shown enlarged in Figure 3, andis more fully described hereafter.

An inlet 2'? for steam is shown near the bottom of the carbonizingchamber, supplied by a vertically disposed conduit 28 passing throughthe assembly aforesaid and fed and supported by a pipe 29.. Pipe 2911connected into pipe 29 indicates a means for admitting oxygen and/or airto the lower portion of the carbonizing chamber to supply any heatrequired for the water gas reaction and/or carbonization of the fuel.

An assembly cap or valve 30, adjustable as by a cable 3| for regulatingthe division of flow of gases through the assembly 26 andthe fuel isshown.

Two regenerative chambers 32 and 32a as indicated in' Fig. 1 and shownin Fig. 2 are connected to the passageway 22 of the producer throughpassageway 33 andvalved inlets 34 and 3411. These regenerative chambersare connected to a stack 36 and an air preheater 36a through valvedoutlets 35 and 3511. This preheater preheats the combustion air to theregenerators and has air inlet and outlet as indicated at 36a and 36a".

Each regenerator is adapted for the combustion of producer gas thereinentering through passageway 33, valves 34 and Me with combustion airadmitted through air inlets 31 and 31a into the respective combustionchambers, only one of which is shown and referenced 38. Each regeneratoris equipped with valved steam inlet means 39 and 39a and valved steamoutlet means 40 and Illa connected into steam supply pipe 29 leading tothe carbonizing chamber in the producer.

The valved steam inlet means are equipped with pressure regulators 4!and Ma to control the pressure of steam admitted to theregenerativechambers. This control is effected by a pres sure pipe 42 opening intogas passageway 20 of the producer. The gas burner 24- is shown equippedwith suitable air mixing means 24a for regulating the combustion airadmitted through pipe 43; I

Combustion is effected. in the boiler combustion chamber or firebox 44with the combustion products passing through the tubes and thencethrough opening 45 into an air preheater 46 having a stack outlet 41.The combustion chamher may be substantially reduced in volume with heatradiating surface provided as indicated by the line a with resultanteconomies. The combustion and producer. air may be supplied by a fan orblower 48 with preheated air .offtakelt from the air preheater leadingto the boiler bumer 24 through pipe 43 and to the producer andregenerative chambers as before described.

stack gas passageways 50 and 5] are shown leading to a blower 52 forwithdrawing the stacl-rgases either from the inlet or outlet of the airpreheaters and delivering these gases through pipe 53 to level ll in theproducer. When the air inspirating effect of the air admitted throughIla to inspirator i8 is relied on for drawing the stack gas into theproducer, the blower 52 may be dispensed with. d

' The produceris shown with a hearth 54 preferably sloping toward a slagdischarge opening 55 which is normally closed by any suitable means suchas fireclay. A second slag discharge open- .ing 55a is shown at a higherlevel for use when iron or metallic ore is charged with the fuel as ai'iuxing agent.- The metal may be drawn off at the lower level 55 withthe slag drawn off at the higher level 55a. v I

The pipe 56 opening into air inlet at level l6 indicates admission meansfor gas or oxygen for farther point as is desired.

In the partial plan view of Fig. 2, a generator section on theline A--Aat level I6 in Fig. 1 is shown. Air inlet headers are indicated at l6and I6, and tuyere openings in the long sides of the 1 generator sectionare indicated at l6". Doors are indicated at El opening into thegenerator through removable blocking as 62. The jets of air and stackgas and/or steam from the tuyres in the long sides of the generatorpractically cover the hearth thus insuring an active use of the entirehearth area.

In Fig. 3, an assembly 26 is shown in a fragmentalr section of thecarbonizing chamber I4 with steam and/or oxygen and/or air admissionmeans 21 supplied by pipes 28, 29 passing through the assembly asdescribed for Fig. 1.

This assembly is preferablymade of a series of open cylinders or cones66 of any desired form and preferably in the form of truncated coneswith the bottom of each cylinder or cone projecting over and below thetop of the next lower one thus forming a protective skirt around theupper end of the next lower cylinder or cone to prevent fuel fallingtherein and to provide annular openings 61 for the escape of volatilematter from the fuel into the open passage through the series ofcylinders as indicated by arrows.

Fig. 4 shows a fragmentary section of a generator wall with an air blasttuyre therein. The tuyeres at each level are supplied by tuyere headerpipes I I, which are supplied by air distributing pipe through valves12. The tuyre nose I3 is shown projecting beyond the generator wall andcooled by water-entering through pipe 14 and discharging through pipe'I4a.

The pipe 56, shown inserted in a tuyere, indicates means for theintroduction of combustible gas or oxygen for mixing with the air andfurthering combustion at this level.

Fluxing material in powered form may also be so admitted into theblasting air through pipe 56.

The improved process is carried out in the apparatus described, asfollows:

A fire is kindled on the producer hearth 54 and the producer filled withfuel (preferably coke at the start) which is replenished with preferablybituminous fuel thereafter through charging opening 15. Valve 23, whenprovided, 7 is open. Air is admitted through tuyeres at level 16. At thestart the lower slag opening 55 may be left open so some burned gasesmay be discharged here with a resultant drawing down of the heat tohighly heat the hearth. As air is admitted and the fuel bed becomes hotthe oxygen of the air is burned to CO2 at first and then decomposed intocarbon monoxide mostly. This gas passes up through the fuel bed,preheating the fuel, leaving it at passage 20, and passing around thecarbonizing chamber, passes out to the boiler through passageway 23 andburner 24.

Air for effecting combustion of this gas is admitted through 43. Thegasis burned in com- .bustion chamber 44, and passing through the boilerenters the preheater 46 through opening 45. This preheater may be of therecuperative type but is preferably of the regenerative type and adaptedfor operation at high stack temperatures, say 800 deg. and more.

The burned gases in passing through the preheater 46 preheat the airadmitted to the preheater as through fan 48, the preheated air beingtaken off at 49 and'supplied to the boiler burner through 43 and to theproducer at levels l6 and I! as desired. As blasting with the aircontinues at level IS, the heat liberated by the burning of the carbonto carbon monoxide continually increases the fuel bed temperature. Whenthe desired fuel bed temperature is reached stack gas drawn off hot at45 ahead of the air preheater or at 5| in the outlet of the preheatermay be valved inlets 31 and 3'|-a. While one regener-' ator is beingheated, steam is admitted to the other through valved inlet 39 and 39-a,and is passed superheated through valved outlets 40 and 4lJ-a into thebottom of the carbonizing chamber through inlet 21. The highlysuperheated steam so admitted in contact with the hot carbon in the baseof the carbonizing chamber forms some water gas and this with anyundecomposed steam more or less blankets the bottom of the carbonizingchamber against the admission of the low grade producer gas.

The water gas and steam and/or producer gas I tillation gases which aredrawn ofl at 58 may be effected.

The blue gas and steam and any producer gas mixed therewith in passingthrough the cylin-.

ders of the assembly produce a vacuum effect which draws the gas fromthe fuel being carbonized in through the annular spaces 61 into thestream of gas. The gas and vapors are accordingly withdrawn from thefuel substantially as evolved and, mixed with the blue gas and steam,leave the assembly through 38 and pass out through 58.

The heat for carbonizing the fuel is supplied by the sensible heat ofthe blue gas and any undecomposed-steam passing through it and theassembly and is supplemented by:

(a)The heat in the producer gas passing around the carbonizing chamber.

(b)--The use of additional amounts of excess steam preferablysuperheated to the highest practicable extent as above described. by thecombustion of a portion of the producer gas in regenerative chamber.

(c)Passing part of the producer gases through the carbonizing chamberand using the sensible heat thereof, and/or 7 (d)Admitting air and/oroxygenmixed with or independent of the steam in the lower portion of thecarbonizing chamber as through 21, or equivalent means for effectingcombustion and the liberation of additional heat in the bottom zone ofthe carbonizing'chamber.

The carbonization temperature may accordingly be varied and controlledby the above methods of heating.

The hydro-carbon vapors are drawn off substantially as formed throughassembly 26 and outlet 58 with a recovery of the condensiblehydro-carbons in liquid form with little or no difliculty from the fuelarching or sticking during carbonizing. a a

The volatile matter of bituminous fuels is of varying composition anddistillable at different temperatures. The volume and quality of thevolatile matter given off varies with the temperature and time ofheating. When the volatile matter distilled oil at relatively highertemperatures passes through cooler fuel some or all of it is condensedon the, cooler fuel. This condensate incases the lumps or particles offuel in a liquid envelope often of a plastic nature which is not againvaporized until the fuel passes into a zone of higher temperature.Meanwhile the lumps and particles contain volatile matter distillable atrelatively lower temperatures which,

,' being partially :or wholly confined within the condensible portion ofthese hydro-carbons may be recovered in liquid form.

With the hydro-carbons drawn off as formed and cracking avoided, theheat required for car-=- bonization is substantially less.

The invention contemplates the distillation of the fuel undercontrollable temperature conditions to permit the evolving and recoveryof condensible hydro-carbons of varying qualities as desired.

The passage of the producer gases around the carbonizing chamber insuresthe relativelyrapid heating and carbonization of the fuel in contactwith the chamber wall. The admission of highly superheated steam and/orair and/or oxygen in the lower zone of the carbonization chamber and itspassage through the fuel and the assembly insures the drawing off of thevolatile matter under temperature and partial pressure conditions whichavoid condensation and permit the recovery of the oils'and rich gases.The use of suflicient undecomppsed steam, assistsin the devolatilizationof the fuel and results in the formation of ammonia, which mixed withthe rela tively small volume of rich gases is easily recoverable. 5

The steam or stack gas enters the fuel at level II, asufficient distanceabove level-J6 so as to bypass the lower intensely hot zone without anappreciable cooling action on any liquid slag in that zone.

With the producer, boiler, and regenerators at the desired temperaturethroughout for regular operation, highly superheated steam and/or air oroxygen is admitted in the bottom zone of the carbonizing chamber and theresultant gases, oil vapors, and ammonia are continually drawn off at58, the carbonized fuel descends into the producer gas generating zonei3, where it is con tinually blasted by highly preheated air from airpreheater 46, with the temperature controlled by steam or stackgasseparately or mixed with air admitted at the higher level forcontrolling fuel bed temperatures.

Any fluxing material, as limestone, charged with the fuel for loweringthe melting point of the ash has the additional advantage of furthering.the production of ammonia. It also carries down a substantial part ofthe sulphur in the fuel ,into 'the slag.

With the stack gases leaving the boiler at relatively high temperaturesand used for preheating air, the boiler heating surface 44a providedoperates at a higher temperature differential with an increase inheat'transfer per unit of heating surface. With stack gases preferablyhot used as an endothermal agent in the producer, practically all thesensible heat in this portion of the stack gases is returned to theprocess. The higher the preheat in the air to the producer, the greateris the cooling action required for keeping the fuel bed temperature downto any desired point. The hotter the'stack gases used as an endothermalagent, the more of these gases may be used for a given amount of coolingand the more nearly is an approach made to a closed heat cycle with areduction in the volume of ducer insures a relatively higher mass of theair to be preheated than in the outgoing stack gases, with a more nearlycomplete'recovery of heat in the waste gases than is obtainable withusual methods.

The use of a portion of the producer gas for combustion in regeneratorsfor superheating steam further increases the mass of the air tobepreheated in proportion to the stack gases -from the boiler orfurnace.

The air preheater SG-m recovers any otherwise waste heat from'theregenerators and preheats the combustion air for the regenerators. Whenthis preheater is used the. valve 49a in Fig. 1 is closed. When air frompreheater 46 is used in the regenerators valve 36a" is closed.

,The invention provides for the production, utilization and recovery ofcombustible gases and by-products of various qualities from a variety ofcarbonaceous fuels.

The steam superheating regenerators may be dispensed with whenever it isdesired to immediately burn all of the gases produced, in. which casethe upper zone of the producer forms the carbonizing chamber withchamber It omitted and the fuel filling the entire upper space.

Combustible gases of different qualities may be produced and recovered,and the steam superheating regenerators dispensed with when the neededheat for carbonizing the fuel is supplied by passing the required amountof producer gas and/or air and/or oxygenthrough the carbonizing chamber.1

The economics and advantages of the difierent features of my inventionare obvious:

Provision is made for the recovery of rich gas, oils, tars, and ammoniafrom bituminous fuel whichis now lost orburned in boiler and otherfurnaces.

The use of controllable amounts of highly superheated steam and/0r airor oxygen and the withdrawal of vapors without condensation insures therapid carbonization of the fuel.

The more valuable constituents of coal are recovered for higher useswith the low grade carbonized residue gasified and immediately used inboilers'or furnaces.

The present limitation in producer gas production occasioned by a fusingtemperatureof the fuel ash is definitely removed by removing the ash inliquid form.

Cheap, abundant fuels are made available for gas production.

Theme of the fluxing material as limestone for liquefying the ash hasthe additional aiilrantage of furthering the production of ammonia andmethane, and carrying sulphur into the slag.

The usual dimculties due to the sticking and with the temperaturetherein controllable within the optimum limits for ammonia formation.

The different features are all combined toprou vide methods for theproduction and recovery oi. rich gas and byproducts from the coal atrelatively high rates in apparatus of a given size with the eflicientproduction and utilization of producer gas in a partially closed heatcycle.

reduction in radiation losses.

The use of stack gases as an endothermal agent limits the formation ofhydrogen and lowers the stack losses by reason of the decreased watervapor content in these stack gases. 1

With the gas used hot as it leaves the producer and mixed with airheated to a relatively high temperature combustion is greatlyaccelerated and the combustion space required for a given capacity issubstantially reduced with a resultant The heat radiating power, of thecarbon monoxide flame is relatively high and with the provision of heatradiating surfaces in the combustion chamber, extremely high rates ofheat transmisson to the boiler or furnace material are obtained.

The reduction of the fuel to ash in the producer results in a relativelyash free gas being delivered to the boiler or furnace with a result thatthe heating surfaces remain clean for an indefinite period, and thefrequent shutdowns, maintenance expense, etc. in present boiler practicenecessitated by ash deposits on the heating surface and the annoyanceand expense caused by the discharge of fine ash with the stack gases isavoided.

From the preceding description, it is evident that the improved methodmakes possible: the recovery of the valuable gases and by-products ofcoal now used in boilers and furnaces on a large scale for higher useswith the immediate consumption of the relatively low grade carbonresidue and the highly efiicientand practically continuous operation ofhigh capacity boilers and furnaces.

While I have herein referred specifically to steam generating boilersand. furnaces, it will be understood that the invention is equallyapplicable to other heat utilizing devices, by which term heat utilizingdevices as used in the description and claims, I mean devices foraccomplishing useful or productive results independent of the producergas generating process proper, that is, useful results extraneous of thegas making cycle proper.

Having described my invention, I claim:

1. In the manufacture of combustible gas from bituminous fuel inapparatus including a gas producer having an upper carbonizingzone and alower producer gas zone and two regenerators, the improvement whichconsists inair blasting the column of fuel in the lower portion of theproducer gas zone, drawing off the pro-- ducer gas formed thereby fromthe upper portion of the lower zone substantially without contact withthe fuel in the carbonizing zone, burning a portion of the producer gasalternately in each of the regenerators, admitting -steam alternately toeach of the regenerators,

passing the steam highly superheated therein from the regenerators tothe lower portion of the carbonizing zone and thereby substantiallyblocking ofl admission of producer gas to the carbonizing zone, passingthe steam through the carbonizing zone, drawing off the distillationgases liberated thereby and admixed therewith from the top of the upperzone, and drawing ofi ash and clinker forming material as liquid slag.

super-heated steam and an oxygen-containing fluid to the lower portionof. the carbonizing zone; and passing such steam and fluid upwardlythrough the carbonizing zone and drawing off the generated and distilledgases liberated thereby and admixed therewith.

3. The herein described improvement in the method of manufacturingcombustible gases from carbonaceous fuels in gas producers having anupper carbonizing zone and a lower producer gas zone which includes:continuously air blasting the column of fuel in the lower portion of theproducer gas zone and maintaining the slag liquid; drawing off theproducer gas thereby formed'from the upper portion of said lower zonesubstantially without contact with the fuel in the carbonizing zone;admitting superheated steam substantially centrally and at the bottom ofthe fuel in the lower portion of the carbonizing zone; and conductingthe steam admixed with the formed and liberated gases from the fuelthrough an apertured passage within the fuel in the upper portion ofsaid carbonizing zone and simultaneously drawing into such admixed steamand gases, the vapors and gases when and as distilled and released fromthe fuel in said upper portion of the carbonizing zone.

4. In the manufacture of combustible gas from carbonaceous fuel in agenerator wherein the fuel descends first through a distillation zoneand thence into an incandescent, up airblasted zone with resultantgeneration of producer gas therefrom, the improvement which consists in:confining the fuel in its passage through the distillation zone to acontinuous solid column of substantially annular form and advancing thefuel downward through said annular column formation solely by gravity;continuously heating said annular colum'n portion of the fuel throughoutits entire height by passing the generated producer gas verticallyupward along the outer side of the annular column portion of fuel butwithout contact of said producer gas with the fuel in the annular columnportion; and, simultaneously with said heating by the producer gas,introducing highly heated fluid into the fuel at the lower portion ofsaid distillation zone, passing said fluid upwardly through said annularcolumn portion of the fuel to effect distillation thereof throughout itsHIRAM J. CARSON.

